<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      // function fn(a, b, ...c) {
      //   console.log(a, b, c);
      // }
      function fn(...c) {
        // console.log(c); = [1, 2, 3, 4, 5, 6, 7]
        return c.reduce((sum, v) => sum + v, 0);
      }
      console.log(fn(1, 2, 3, 4, 5, 6, 7));
    </script>
  </body>
</html>
